Preheat the oven to 375 F. Grate the boiled potatoes. Take eggs, milk and olive oil in a mixing bowl and whisk it. Add grated potatoes, feta cheese,chopped dill and salt. Stir with a spatula.Grease 12" baking dish with butter.Take the mixture into the baking dish and flatten the surface of the mixture.Bake it around 45 minutes or it is golden.Enjoy...